Hi,
I saw your description but please generate the patches against the
latest codes at next time.
On 4/14/12, Prathyush <prathyush.k at samsung.com> wrote:
> With this change, the exynos drm dmabuf module can export and
> import dmabuf of gem objects with non-continuous memory.
>
> The exynos_map_dmabuf function can create SGT of a non-contiguous
> buffer by calling dma_get_pages to retrieve the allocated pages
> and then maps the SGT to the caller's address space.
>
> Signed-off-by: Prathyush K <prathyush.k at samsung.com>
> ---
> drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 98
> +++++++++++++++++++++++-----
> 1 files changed, 81 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> index cbb6ad4..54b88bd 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> @@ -56,6 +56,59 @@ static void exynos_dmabuf_detach(struct dma_buf *dmabuf,
> dma_buf_put(dmabuf);
> }
>
> +
Useless newline.
> +static struct sg_table *drm_dc_pages_to_sgt(struct page **pages,
> + unsigned long n_pages, size_t offset, size_t offset2, dma_addr_t daddr)
> +{
> + struct sg_table *sgt;
> + struct scatterlist *s;
> + int i, j, cur_page, chunks, ret;
> +
> + sgt = kzalloc(sizeof *sgt, GFP_KERNEL);
> + if (!sgt)
> + return ERR_PTR(-ENOMEM);
> +
> + /* compute number of chunks */
> + chunks = 1;
> + for (i = 1; i < n_pages; ++i)
> + if (pages[i] != pages[i - 1] + 1)
> + ++chunks;
> +
> + ret = sg_alloc_table(sgt, chunks, GFP_KERNEL);
> + if (ret) {
> + kfree(sgt);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + /* merging chunks and putting them into the scatterlist */
> + cur_page = 0;
> + for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
> + size_t size = PAGE_SIZE;
> +
> + for (j = cur_page + 1; j < n_pages; ++j) {
> + if (pages[j] != pages[j - 1] + 1)
> + break;
> + size += PAGE_SIZE;
> + }
> +
> + /* cut offset if chunk starts at the first page */
> + if (cur_page == 0)
> + size -= offset;
> + /* cut offset2 if chunk ends at the last page */
> + if (j == n_pages)
> + size -= offset2;
> +
> + sg_set_page(s, pages[cur_page], size, offset);
> + s->dma_address = daddr;
> + daddr += size;
> + offset = 0;
> + cur_page = j;
> + }
> +
> + return sgt;
> +}
This function is almost same as Tomasz one at v4l2.
To Tomasz,
Can you make it common helper function at common place?
> +
> +
Useless newline too.
> static struct sg_table *exynos_map_dmabuf(struct dma_buf_attachment
> *attach,
> enum dma_data_direction direction)
> {
> @@ -64,6 +117,8 @@ static struct sg_table *exynos_map_dmabuf(struct
> dma_buf_attachment *attach,
> struct exynos_drm_gem_buf *buffer;
> struct sg_table *sgt;
> int ret;
> + int size, n_pages;
> + struct page **pages = NULL;
>
> DRM_DEBUG_KMS("%s\n", __FILE__);
>
> @@ -71,27 +126,37 @@ static struct sg_table *exynos_map_dmabuf(struct
> dma_buf_attachment *attach,
>
> buffer = exynos_gem_obj->buffer;
>
> - /* TODO. consider physically non-continuous memory with IOMMU. */
> + size = buffer->size;
> + n_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
>
> - sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> - if (!sgt) {
> - DRM_DEBUG_KMS("failed to allocate sg table.\n");
> - return ERR_PTR(-ENOMEM);
> + pages = kmalloc(n_pages * sizeof pages[0], GFP_KERNEL);
kcalloc?
Thank you,
Kyungmin Park
> + if (!pages) {
> + DRM_DEBUG_KMS("failed to alloc page table\n");
> + return NULL;
> }
>
> - ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> + ret = dma_get_pages(attach->dev, buffer->kvaddr,
> + buffer->dma_addr, pages, n_pages);
> if (ret < 0) {
> - DRM_DEBUG_KMS("failed to allocate scatter list.\n");
> - kfree(sgt);
> - sgt = NULL;
> - return ERR_PTR(-ENOMEM);
> + DRM_DEBUG_KMS("failed to get buffer pages from DMA API\n");
> + return NULL;
> }
> + if (ret != n_pages) {
> + DRM_DEBUG_KMS("failed to get all pages from DMA API\n");
> + return NULL;
> + }
> +
> + sgt = drm_dc_pages_to_sgt(pages, n_pages, 0, 0, buffer->dma_addr);
> + if (IS_ERR(sgt)) {
> + DRM_DEBUG_KMS("failed to prepare sg table\n");
> + return NULL;
> + }
> +
> + sgt->nents = dma_map_sg(attach->dev, sgt->sgl,
> + sgt->orig_nents, DMA_BIDIRECTIONAL);
>
> - sg_init_table(sgt->sgl, 1);
> - sg_dma_len(sgt->sgl) = buffer->size;
> - sg_set_page(sgt->sgl, pfn_to_page(PFN_DOWN(buffer->dma_addr)),
> - buffer->size, 0);
> - sg_dma_address(sgt->sgl) = buffer->dma_addr;
> + /* pages are no longer needed */
> + kfree(pages);
>
> /*
> * increase reference count of this buffer.
> @@ -303,8 +368,6 @@ int exynos_dmabuf_prime_fd_to_handle(struct drm_device
> *drm_dev,
> if (ret < 0)
> goto fail_handle;
>
> - /* consider physically non-continuous memory with IOMMU. */
> -
> buffer->dma_addr = sg_dma_address(sgt->sgl);
> buffer->size = sg_dma_len(sgt->sgl);
>
> @@ -316,6 +379,7 @@ int exynos_dmabuf_prime_fd_to_handle(struct drm_device
> *drm_dev,
> atomic_set(&buffer->shared_refcount, 1);
>
> exynos_gem_obj->base.import_attach = attach;
> + exynos_gem_obj->buffer = buffer;
>
> ret = drm_prime_insert_fd_handle_mapping(&file_priv->prime,
> dmabuf, *handle);
> --
> 1.7.0.4
>
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